Changing transmission fluids and filter, and I’d like to go with synthetic Mobile 1 this time around and moving forward.
I was reading old posts (2016) and someone mentioned an MB 1 formulation change; does that present any issue? Also some of the comments referenced the 722.6 transmission, and I’m not sure if that would take the same fluid. The ATF isle at the parts store confuses the snot out of me as I try to make sense of the various formulations available, and second guess myself.
Specifically, what Mobile One ATF should I purchase? Is it marked “Dexron/Mercon”?
Thanks for your help.

My 89 300E with a 722.3 has been using synthetic Mobil 1 ATF since 2016 without problems. Still drives and shifts just fine.

I also use M1 synthetic ATF in my 717.411 manual gearbox on my 190E.

Thanks for the reply John.
At the risk of appearing stupid, but just to be clear; is it Mobil 1 Dexron/Mercon that I’m after?

The 722.3 takes Dexron III, so the Dex/Merc fluid should be fine. The 722.6 takes a different fluid.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Thanks 300. It appears that Mobil 1 has one type of multifunction fluid that’s just marked ATF. It lists Dexron and Mercon on the back label. This must be what John is useing with good results.
Thanks to both you guys.

I have owned a 1991 300-SEL since 1997 and have used what Diseasel300 pointed out - Dexron-III. This is what the '91 owners manual calls for. Car has always shifted smoothly.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

Thanks Mike.
I find the ATF topic, with it's varying classifications very confusing. I can't even find Dexron III anywhere. It has been upgraded to Dexron IV. With most labels just stating DEX/Merc. The data that I see say's that in MOST cases the IV is backwards compatible to the III, and the II; but not always. Then, Dexron, is always, as far as I can tell, paired with the word Mercon or Merc on the labels. The Mobil 1 ATF, is just marked ATF, and they mention Dexron on the back label, but you have to search for it. In the past, I have just used Valvoline Dex/Merc. Are you guys finding ATF marked as Dexron III?

Quaker State, Pennzoil, NAPA and many others continue to sell Dex III. You may not clearly see Dex-III on the front or rear labels. I have a bottle of Quaker State in my hands now that says:

Quaker State Automatic Transmission Fluid ATF - green bottle - in the lower right corner of the label I see:

For use in vehicles previously serviceable by Dexron-III/Mercon Brands

Look on the bottles for the statement above in bold.

This stuff is all over the place - Walmart - Dollar Stores - Auto Parts stores.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"

My 325,000 mile 300SEL, with the original trans, uses whatever is cheapest and on sale...this is usually Autozone brand and at times Walmart. Pretty sure Warren packs both.

Most important thing is you are actually servicing the unit.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

I’ve seen Dex VI which a 722.3 runs with no problems. I’ve never seen Dex IV.

Sixto
98 E320s sedan and wagon
02 C320 wagon

325k on an unopened transmission is very impressive Hit Man. You got me thinking maybe the MB1 is overkill and may just go back to Valvoline, with a regular maintenance schedule.
Sixto, IV was my typo. Meant to say VI. Roman numerals are confusing as ATF specs.
Thanks for the help.

Reverse is very, very slow in the 300SEL. Easily four, maybe five seconds.

Well, does that Superior Shift kit count? It VASTLY toned down that harsh 1-2 upshift. Nothing was broken in the valve body, nor was it heavily soiled.

The 300E did not shift great, but still did around 270k when it died. The rest are in the 250k area.



Otherwise, auto trans failure is abuse or lack of maintenance to me!



I think Dex VI is current formulation.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Valvoline Dex/Merc III is the stuff. You can get the MB Dex III, but the Valvoline is half the price and sufficient. Most any parts store carries Dex/Merc.

I've been using Dexron VI Full Synthetic in all of my 722.3 trans cars for several years. Usually the stuff from Valvoline. In the cold especially the shifts are a lot smoother vs Dexron III non synthetic.

__________________
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